ebay 103c8t6 oled, nrf24, esp8266 + empty pads

Generic boards that are not Maple or Maple mini clones, and don't contain the additional USB reset hardware
RogerL
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Joined: Wed Jul 08, 2015 12:54 pm
Location: England

Re: ebay 103c8t6 oled, nrf24, esp8266 + empty pads

Post by RogerL » Sat Dec 24, 2016 2:42 pm

Post deleted (I read the Wicki! :oops: )
Last edited by RogerL on Fri May 19, 2017 3:57 pm, edited 1 time in total.

aroldorosenberg
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Joined: Tue Jan 03, 2017 3:29 pm

Re: ebay 103c8t6 oled, nrf24, esp8266 + empty pads

Post by aroldorosenberg » Tue Jan 03, 2017 3:44 pm

I have bought a few of those boards. One weird thing about them is that the SDA and SCL pins in the EEPROM pads are not connected to hardware I2C pins, but rather to PB4 and PB6. If you solder two 10k 0603 resistors to the R12 and R13 pads, you can use the PB4 and PB6 pins as software I2C pins without using external pullup resistors as you would by using the PB6 and PB7, which are the hardware I2C1 pins. You do need to modify the Wire.cpp in order to use the PB4 and PB6 pins. Now, here's what is funny: PB4 and PB6 are used by both the SPI1 and Serial1 interfaces, which also have alternate pins. I wonder if someone could include an option in the Wire.h to let people choose which pins they use as I2C pins with a couple of defines, since what there is in place are two lines like:

Code: Select all

// Declare the instance that the users of the library can use
//TwoWire Wire(SCL, SDA, SOFT_STANDARD);
//TwoWire Wire(PB6, PB7, SOFT_STANDARD); // this is how the wire.cpp file originally is
TwoWire Wire(PB4,PB6,SOFT_STANDARD); // EEPROM pins in the blackboard
Anyway, this is a very nice board, I wonder if we could get the manufacturer to make a better version of it :)
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zmemw16
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Joined: Wed Jul 08, 2015 2:09 pm
Location: St Annes, Lancs,UK

Re: ebay 103c8t6 oled, nrf24, esp8266 + empty pads

Post by zmemw16 » Tue Jan 03, 2017 6:28 pm

please, please, it would be really nice if you put up a picture of whatever connections are hiding behind the board and display.

there is probably more documentation than anything else on this machine, from A Touch of Frost - lottery win - he lost it;
" paperwork Jack, i keep telling you, paperwork" !
or something close.

i've only just again found my SMT soldering station.
but my 24c256's have arrived which is what prompted the search, solder is next ... ... ... paper index after that !

stephen

aroldorosenberg
Posts: 5
Joined: Tue Jan 03, 2017 3:29 pm

Re: ebay 103c8t6 oled, nrf24, esp8266 + empty pads

Post by aroldorosenberg » Tue Jan 03, 2017 8:28 pm

zmemw16 wrote:please, please, it would be really nice if you put up a picture of whatever connections are hiding behind the board and display.

there is probably more documentation than anything else on this machine, from A Touch of Frost - lottery win - he lost it;
" paperwork Jack, i keep telling you, paperwork" !
or something close.

i've only just again found my SMT soldering station.
but my 24c256's have arrived which is what prompted the search, solder is next ... ... ... paper index after that !

stephen
The display is just one of those 20x4 displays with an i2c port expander. Behind the board, near the eeprom footprint, there are pads for two resistors, labelled R12 and R13. I soldered in two 10k resistors, and that's about it. There really is nothing about this board that can't be seen on the listings.

zmemw16
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Joined: Wed Jul 08, 2015 2:09 pm
Location: St Annes, Lancs,UK

Re: ebay 103c8t6 oled, nrf24, esp8266 + empty pads

Post by zmemw16 » Tue Jan 03, 2017 10:48 pm

@aroldorosenberg

i was after the circuit/sketch on the paper, there were some strange to me at least port numbers. i suspect that's the esp socket?
for example my 103rc boards with just a nrf24 socket, it's on spi 1 pins a4-a7 with cs & irq on port c4 & c5 istr

regarding alternate functions, 407xx pdf has 9 pages of it, i'm wondering if there's the same or more for 103. what chance the same mapping ????

stephen

aroldorosenberg
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Joined: Tue Jan 03, 2017 3:29 pm

Re: ebay 103c8t6 oled, nrf24, esp8266 + empty pads

Post by aroldorosenberg » Tue Jan 03, 2017 11:55 pm

I was just trying to figure out which pins of the NRF24/ESP8266 connectors were connected to, it's nothing other people haven't found out already in this thread ;)

zmemw16
Posts: 1294
Joined: Wed Jul 08, 2015 2:09 pm
Location: St Annes, Lancs,UK

Re: ebay 103c8t6 oled, nrf24, esp8266 + empty pads

Post by zmemw16 » Thu Jan 05, 2017 12:55 pm

regarding alternate functions, 407xx pdf has 9 pages of it, i'm wondering if there's the same or more for 103. what chance the same mapping ????
well, found them and most definitely not the same format / mechanism
RM0008 Reference Manual STM32F101xx, STM32F102xx, STM32F103xx, STM32F105xx and STM32F107xx advanced ARM®-based 32-bit MCUs
November 2015 / DocID13902 Rev 16 / 1137 pages

and its 21 or so pages for the 103. start page may well be early at 174(182??) ends about 195.

stephen

aroldorosenberg
Posts: 5
Joined: Tue Jan 03, 2017 3:29 pm

Re: ebay 103c8t6 oled, nrf24, esp8266 + empty pads

Post by aroldorosenberg » Fri Jan 06, 2017 11:24 pm

I soldered in a micro-sd card slot and 3 10k resistors in the nearby pads, as per the schematic.

Guess what?

Works perfectly with the default SD library. Chipselect pin is PA4. It could use an activity led to indicate when the pin is pulled low, like on some micro-sd card readers.
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zmemw16
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Location: St Annes, Lancs,UK

Re: ebay 103c8t6 oled, nrf24, esp8266 + empty pads

Post by zmemw16 » Mon Jan 16, 2017 11:27 am

i've just re-read this thread.
oh, so i didn't actually need to solder those resistors in :roll:
srp

aroldorosenberg
Posts: 5
Joined: Tue Jan 03, 2017 3:29 pm

Re: ebay 103c8t6 oled, nrf24, esp8266 + empty pads

Post by aroldorosenberg » Sun Jan 22, 2017 12:10 am

The cheap nrf24l01 modules most of us are familiar with work quite well on them, by the way. Both the small, with the PCB antenna, and the bigger one with a SMA one.


https://www.instagram.com/p/BPi56h-jUUe

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